M5: a callout's leader line follows its text box while the box is resized (#1152)

Review on #4094: resizing a callout's text box moved its frame, but
changing_points had no Resize branch, so no leader line was drawn to the box
until the page was redrawn. A Resize gesture, and the ResizeAnnotation edit
just released, now count as changing the callout: its points stay and its
line is drawn to where the box is going. A box moved alone and released keeps
its knee beside it, as while it was dragged.

Test: a_callout_being_resized_draws_its_leader_line, which fails with the fix
reverted.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Pq7HyCfwzyRXj4VfQAVVdv

crates/ui-egui/src/tools/comments/paint.rs

@@ -100,6 +100,10 @@ pub(super) fn changing_points(
         }),
         (_, Some(Edit::ReshapeAnnotation { page: p, index: i, points: to })) if (*p, *i) == (page, index) => Some(to.clone()),
         (_, Some(Edit::MoveAnnotation { page: p, index: i, dx, dy })) if (*p, *i) == (page, index) => Some(shifted(*dx, *dy)),
+        // A callout's text box resized (or moved alone): its points stay, and its line is drawn to
+        // the box where it is going (see `paint_points`).
+        (Some(Gesture::Resize { page: p, index: i, .. }), _) if (*p, *i) == (page, index) => pointer.map(|_| points.to_vec()),
+        (_, Some(Edit::ResizeAnnotation { page: p, index: i, .. })) if (*p, *i) == (page, index) => Some(points.to_vec()),
         _ => None,
     }
 }
@@ -119,6 +123,19 @@ fn paint_points(painter: &egui::Painter, cx: &PageCx<'_>, view: &DocView, a: &An
     {
         *p = [f64::from(first[0]), f64::from(first[1])];
     }
+    // A callout's box moved alone and released: its knee came along, as while it was dragged.
+    if let (Some(Edit::ResizeAnnotation { page, index, rect }), Some(tb)) = (view.pending_edit.as_ref(), a.text_box.filter(|_| is_callout(a)))
+        && (*page, *index) == (cx.page, a.index)
+    {
+        let tb = tb.map(f64::from);
+        let same = |a: f64, b: f64| (a - b).abs() < 0.01;
+        if same(rect[2] - rect[0], tb[2] - tb[0]) && same(rect[3] - rect[1], tb[3] - tb[1]) {
+            let (dx, dy) = (rect[0] - tb[0], rect[1] - tb[1]);
+            for q in points.iter_mut().skip(1) {
+                *q = [q[0] + dx, q[1] + dy];
+            }
+        }
+    }
     let screen: Vec<Pos2> = points.iter().map(|q| cx.to_screen(*q)).collect();
     if changed {
         let stroke = Stroke::new(1.5, SELECT_BLUE);

crates/ui-egui/src/tools/comments/tests.rs

@@ -24,6 +24,20 @@ fn a_moved_or_reshaped_line_is_drawn_at_its_new_points() {
     assert_eq!(changing_points(None, None, (0, 3), &line, to_user, to, straight), None, "not changing");
 }
 
+/// Review on #4094: a callout's text box being resized, and the resize just released, draw its
+/// leader line too (to the box where it is going): its points are changing, though they stay.
+#[test]
+fn a_callout_being_resized_draws_its_leader_line() {
+    let lead = [[10.0, 10.0], [40.0, 30.0]];
+    let to_user = |p: Pos2| [f64::from(p.x), f64::from(p.y)];
+    let resizing = Gesture::Resize { page: 0, index: 3, handle: (1, 1), from: pos2(80.0, 60.0), aspect_ratio: None };
+    let at = Some(pos2(95.0, 70.0));
+    assert_eq!(changing_points(Some(&resizing), None, (0, 3), &lead, to_user, at, straight), Some(lead.to_vec()));
+    assert_eq!(changing_points(Some(&resizing), None, (0, 4), &lead, to_user, at, straight), None, "another comment's resize");
+    let released = Edit::ResizeAnnotation { page: 0, index: 3, rect: [50.0, 20.0, 110.0, 70.0] };
+    assert_eq!(changing_points(None, Some(&released), (0, 3), &lead, to_user, None, straight), Some(lead.to_vec()));
+}
+
 /// A sticky note on a page turned a quarter is drawn upright beside its `/Rect`: an edit
 /// composer stays open while the drawn note is partly in view, even with `/Rect` out of it.
 #[test]